This exercise is to show the effect the speed of the shutter has on movement, it can either freeze it still or in turn blur the movement and in occasions give the illusion of movement within the subject. We achieve this by varying the shutter speed and in the images below I have used a car being driven from left to right at 30mph in each image to give a constant and accurate depiction of the difference each image at different speeds gives.This first image was taken at 1/4000th of a second and shows the car completely frozen with not a hint of movement due to the speed of the shutter.
This image was taken at 1/500th of a second and now we start to see the slight movement in the wheels being blurred on the rotation, however this still keeps the body of the car sharp due to the added movement of the wheels compared to the body of the car passing across the photograph.
This image taken at 1/350th of a second starts to show any real movement on the subject as a whole however slight, the movement of the wheels is still the primary evidence of movement however the brake lights and wing mirror both show a small amount of motion blur when looked at closely.
This was taken at 1/250th of a second and again similar to the one above it really starts to show motion blur throughout the length of the car, the wheels however now look to have a much more complete blur.
This was taken at 1/15th of a second and again really shows the movement across the image, capturing within that time what looks like 2 wheel lengths of distance. The blurred movement is also useful especially in other subject matters and images to show the direction of movement as it does above.
We first started to see movement at 1/500th and 1/350th a second with both times just the wheels being blurred as the wheels move at a higher rate over the time than the car as a whole. This can give the subtle hint of movement thus showing speed but still keeping the car in a manner in which it is recognisable and sharp.